Thermodynamics A diffuser is a device used for slowing the f

?Thermodynamics

A diffuser is a device used for slowing the flow down. Air at -30 degree C and 80 kPa enters a perfectly insulated diffuser of a jet engine with a velocity of 300 m/s. The inlet area is 0.2 m^2. Air leaves the diffuser with a velocity of 100 m/s. The exit pressure is 90 kPa. Temperature of air leaving the diffuser is (in degree C).

Solution

The answer can be gotten from the energy eqaution:

P/rho + V^2/2g + CpT = constant

from conditions at inlet 1 and exit 2,

Cp(dT) = -12/rho + (Vin^2-Vout^2)/2g

Find Cp and rho and use correct units to get dT which gives the answer.